


A Potion Doesn't Fix Everything

by GummiStories



Category: Shadowhunters (TV)
Genre: Arranged Marriage, First Meetings, I hope you like this! :D, M/M, Merman Alec, Merman magnus, Royal Alec Lightwood, Sea Witch Magnus, Slow Burn, merfolk
Language: English
Status: In-Progress
Published: 2020-06-26
Updated: 2021-02-21
Packaged: 2021-03-04 04:16:18
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 4,673
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24927562
Author URL: https://archiveofourown.org/users/GummiStories/pseuds/GummiStories
Summary: Alec Lightwood is the prince and next in line for the throne of Alicante, meaning he has to marryOnly problem is that he must marry a mermaid, rather than a fellow merman as he wishedTo ensure that his future doesn't leave him miserable, Alec seeks out the help of the evil and cynical sea witchHowever, it seems that Magnus isn't what everyone makes him out to beDoes Magnus truly want the Lightwood prince to be happy?AkaGay merman boyfriends are gay and adorable
Relationships: Magnus Bane/Alec Lightwood
Comments: 12
Kudos: 72





	1. Chapter 1

“You must never go near the sea witch, he’s a cruel and vile man. He wants nothing but suffering”

“He’s nothing but trickery, he’ll take your coin and leave you with nothing”

“I heard he eats those who don’t pay him fairly”

Despite all the warnings Alec had drilled into his head his entire life, Alec was swimming deeper and deeper into the depths of the ocean towards the sea witches lair. This was Alec’s final hope for a happy life, a life where he loved his future wife and would fulfil the destiny that had been set out for him since he was born.

The sea witch was infamously known for being able to change people with magic, potions and whatever else he could make up, surely he would be able to help Alec… right?

The water seemed to get colder as the sea witches’ cave came into view, it sent a chill down Alec’s spine at the thought of what could be lurking inside. But he needed to do this, he had no other choice; it was his duty. Pulling his hood higher up over his head, Alec swam inside.

The cave entrance was chilly and dark, only gently lit up by bioluminescent plants that littered the floor and walls. It was just what would pop into your mind when you thought “evil sea witch”, everything so suspicious and ominous. 

After a small swim, the tunnel opened up into a cavern which looked to be like a sitting room, it was rather well decorated for a cave. Alec cleared his throat and straightened up ready to announce his presence.

“Hello? Magnus Bane? I’m here to speak with you” Alec said confidently, showing fear would be the worst possible thing he could have done right now.

“Alexander Lightwood, here, in my lair… well isn’t this a surprise” A voice echoed throughout the room, sending a chill down Alec’s spine.

“I need your services” Alec continued, only to be met with silence. Alec waited a few more moments before another merman slowly slinked into the room, taking Alec’s breath away with his entrance.

The merman in front of him was most likely Magnus Bane, the sea witch. His tan skin met beautifully shiny obsidian and golden scales which seemed to shimmer even in the low light. His torso was decked out in silks, jewels and jewellery, matching his perfectly styled hair and flawless makeup. Everything about the sea witch screamed confidence.

“What on earth could a Lightwood want from a lowly sea witch such as myself hmm?” Magnus smirked as he began to circle Alec like a hungry shark would stalk their prey. Looking him up and down, Magnus took in the prince's well-toned figure, dark and beautiful eyes. His scales were a beautiful mix of aqua and light blue, they were stunning to look at and clearly showed his royal status. Alec refused to be phased and pulled down his hood, meeting Magnus’ eyes as he stopped in front of him again.

“I need you to make me normal, I will pay anything you require” Alec stated firmly, slight worry settled over Alec when the sea witch frowned at him crossing his arms

“Normal? What on earth do you mean by normal? If you mean not making you royalty, there is nothing I can do by that” Magnus looked him up and down with a suspicious look

“No, no, not like that. I am to be wedded in a week, to a mermaid as is my duty as the prince but I… I am not attracted to females, I will be miserable living a lie for the rest of my life. So that’s why I need your help, you have to be able to whip up something that can change me, something that makes me how I’m supposed to be” Alec explained quickly, being so transparent with someone outside of the royal family was forbidden, it wasn’t like Alec had a choice, however.

Looking up from where Alec had been playing with his hands, he was met with Magnus’ shocked face, the sea witches’ mouth opened and closed once in an attempt to say something.

“Can you help me? I have enough riches to cover anything you need, the treasury won’t even miss it” Alec said adding a slight bit of begging to his voice, this was his last chance it _had_ to work.

“You want me… to make you straight?” Alec nodded in response causing Magnus to frown even more.

“Absolutely not” Magnus exclaimed throwing his hands up in the air as he turned around

“What? Magnus, please! I need this! If I don’t I-”

“I refuse to brainwash you into living a lie, I may be a _witch_ but even I have standards” Magnus began to swim down the hall that led from the living area, Alec following hot on his tail

“What else am I supposed to do?! This is my duty as the prince, I can’t not do it!” Alec yelled.

“And why not?! Why do you _have_ to go along with your family’s bigoted and homophobic rules?” Magnus fumed turning around sharply, only to have the prince bump into his chest at the sudden turn.

“Because… because I, I don’t have a choice. Magnus, I know you don’t think it’s right but it’s my duty as a royal and if I don’t do this the kingdom is doomed” Alec explained sadly, every part of Alec’s being wanted him to run off and find his own happiness, but doing so would make the duty of the firstborn fall to his younger sister Isabelle, that wouldn’t be fair on her.

Magnus scrunched up his mouth before letting out a harsh sigh.

“I’m sorry Alexander, but I can’t do this for you” Alec sighed and deflated in defeat, clutching tightly at his cloak. “However” Alec’s head popped up as Magnus continued.

“I want you to give me a week, a week to convince you that you’re worthy of your own happiness” Alec frowned at Magnus’ words.

“You want to… spend time with me?” Alec questioned

“If it convinces you that you are worth having your own future and destiny that you have full control over, then yes, I want to spend time with you Alexander,” Magnus said firmly placing his hands on his hips. Alec frowned and thought about it for a while before sticking out his hand.

“If you haven’t convinced me by the end of the week, you have to make me that potion or whatever, _please_ ” Alec said firmly. Magnus looked between the prince’s face and his hand a few times before nodded and grabbing Alec’s hand.

“Deal”


	2. Chapter 2

**Summary for the Chapter:**

> Time for food, dancin and vibiiiiiiiiiiiin

“I thought you said it wasn’t a good idea for me to be seen out here” Alec mumbled to Magnus as he followed the sea witch closely, Magnus had glamoured his tail to a more dull dark red colour hiding his royal status. Alec felt exposed without his hood but Magnus insisted that he would attract more attention with it on.

“You’re fine Alexander, we’re not far now” Magnus responded as they continued swimming towards the lively neighbourhood that laid before them. As was this was their first day together, Magnus thought it would be a good idea to start with something simple. 

As the prince of Idris Alec was confined to the castle almost 24/7, so giving Alec a small taste of life was like outside was the best way to introduce him into the free life Magnus wanted to convince the prince he could live. In one of the more downworld populated villages, there was a large celebration being held. There was music, dancing and food galore, just the type of scene Magnus enjoyed. 

As Magnus continued to swim towards the entrance of the village he felt Alec’s presence leave his side. With a slight frown Magnus turned around expecting to see Alec distracted by something but to the sea witches’ surprise, the prince was still and staring forward towards the village with anxiety radiating from him.

“Alexander? Is everything alright?” Magnus questioned swimming back over his side.

“I-I… I don’t know if this is a good idea Magnus, maybe we should just go back” Alec suggested gesturing over his shoulder. Magnus could see how scared the prince was, he was unconsciously hugging himself and trying to make himself seem smaller, his hazel eyes slightly widened in fear.

“Hey, everything is going to be just fine,” Magnus said with a comforting smile

“But I know how hated my parents are… if people see me they might think I’m the same and-” Magnus stopped the prince’s yammering with a finger to his lips.

“Alexander, you will be fine. You’re with me and I won’t let anything happen to you, now let's go have some fun, yeah?” Alec sighed and gave Magnus a half-smile before nodding. The two mermen turned and began to make their way into the village.

Alec had never experienced anything like this before. The sounds, the beautiful colours, the way each and every merperson was dressed differently and how everyone looked so happy. In the castle, it was quiet, dull and the uniform of the guards was one of the only things Alec saw daily. Every staff member looked either sad, bored or angry and Alec didn’t blame them, they were working for some of the cruellest people in the sea.

“A bit starstruck Lightwood?” Magnus smirked seeing Alec wide-eyed in awe of the beautiful village surrounding him.

“I’ve never seen anything like this… I mean we have the occasional ball at the palace but that’s just snobs and shitty wine” Alec replied.

“Well, I think it’s about time we get some real alcohol into you” With that Magnus turned and began swimming towards the food and drink area, even from far away you could smell how good everything was over there.

“Now from my very few visits to the palace, I can tell you that the food there is semi-decent but _nothing_ compared to the local food” Magnus explained as the pair approached a stall that was selling assorted spiced and grilled seafood on sticks.

“It’s okay… I guess? I haven’t had anything else to compare it to” Alec shrugged as he watched Magnus smile and pay the woman behind the counter, in return, she gave him two seafood kebabs.

“Alright now honest opinion, I don’t care if you don’t like it or not, even though you will,” Magnus said as he handed one of the kebabs to Alec, who stared at the food in his hands with a slight look of concern on his face.

“It won’t kill you, Alexander, just eat it” Magnus chuckled as he took a bite of his food. With a shrug Alec bit into his food and began to eat, Magnus watching his face as it went through a range of emotions.

“Well?” Magnus questioned as Alec finished his bite. The prince looked between his food and Magnus a couple of times before a small smile appeared on his lips

“This is _amazing_ ” He exclaimed before going in for more, making Magnus smile in response and continue eating his food.

The prince and the sea witch sat together and ate their food, comfortable idle chatter filled the space between them as they enjoyed their lunch, any anxiety Alec had quickly faded. 

“And then the whole thing exploded, right in his face” Magnus laughed recollecting an old memory, smiling, even more, when Alec began to laugh too.

“In front of everyone?” Alec questioned in between laughs

“He didn’t show up to another cabinet meeting for at least 3 months, it was amazing” Magnus replied. He hadn’t known Alec for very long, but seeing him smile and laugh was something that filled Magnus’ chest with joy, his hope of convincing the prince he was worth his happiness going upwards with it.

As Alec opened his mouth to respond, the sound of a loud instrument interrupted him pulling both men’s attention towards the said sound.

“What was that?” Alec questioned with a frown, concern returning to his face.

“Relax your highness, it’s just music,” Magnus said as he put a hand on Alec’s arm.

“Oh… can I, can we…” Alec mumbled wringing his hands together.

“You read my mind!” Magnus exclaimed, his grip on Alec’s arm tightening as he pulled him up and began quickly swimming over to the crowd of people surrounding the dancing area.

Weaving through the people with Alec stumbling behind him, Magnus saw the crowd of people to see many merfolk dancing and twirling on the dance floor, joyous smiles across their faces.

“Let’s dance!” Magnus said with a wide smile turning to Alec who looked back at him in shock

“Dance? Oh no Magnus I don’t, I can’t dance” Alec stammered out only receiving a laugh in response from Magnus

“Not with that attitude! Come on I’m sure you’ve danced at some point in your life” Magnus replied with a cocked eyebrow, an embarrassed blush was spreading across Alec’s face.

“I’ll look like a fool” Alec continued. Magnus gave him a small smile before moving his hand down the prince’s arm and into his hand, holding it gently. Alec looked back up at Magnus at the movement of the sea witch’s hand.

“Just do what feels right and have fun, that’s what’s important,” Magnus said supportingly, giving Alec’s hand a tug towards the dance floor. If the prince didn’t want to dance, Magnus wouldn’t force him, but he really _really_ wanted to see Alec dance.

Alec groaned and rolled his eyes before letting Magnus tug him towards the other dancing mermaids and mermen. How could Alec say no to Magnus when he had that excited look in his eyes? All of the rumours that Alec had been told about Magnus has all but dissolved from his mind whilst spending the past hours with him, none of it was even close to true. 

From what Alec could see, Magnus was just like any other kind-hearted merfolk just with a little bit of extra magic. He wasn’t dark and terrifying, cruel and vicious who wanted nothing but misery. He was a person who enjoyed the simple things in life, simple things that Alec had never been exposed to until Magnus came along.

Said sea witch was currently smiling and swaying back and forth with his hands holding Alec’s, trying to get the prince to dance along with him. Alec followed along as best as he could, hoping he wasn’t doing too bad of a job. 

“See? Isn’t this fun?” Magnus asked as he did some sort of twirl making Alec smile. He couldn’t lie, the sounds of the music and laughter surrounding him were making his insides warm and light, it was an amazing change of pace to his normal castle life.

“I guess so” Alec replied with a smile, the first smile in a long time that didn’t feel forced.

“Your turn!” Magnus exclaimed as he suddenly lengthened his arm before pulling on Alec’s hand sharply, causing the other to begin spinning. Alec let out a yelp in surprise before he landed against Magnus’ chest, a blush quickly flushing his face for the second time that day. Magnus smirked down at him before helping back to his former position.

“Not bad prince” Magnus teased causing Alec to smirk

“All those dance lessons my mother made me attend must have paid off” Alec replied, Magnus gave a half-hearted frown.

“I thought you said you didn’t dance” 

“Not for snobby merfolk who wish to marry me, for you though? I’ll make an exception”

**Notes for the Chapter:**

> Follow my tumblr!
> 
> http://gummi-stories.tumblr.com/


	3. Chapter 3

**Summary for the Chapter:**

> Alec and Magnus go hunting... fishing? Underwater fishing hunting...

“You’re holding it wrong, Alexander”

“What do you mean I’m holding it wrong, how else am I supposed to hold it?”

“You’re using two hands, you’ll be able to get better power if you only use one” 

“Like this?” Alec questioned as he let go with one of his hands, his other remaining close to the tip of the spear

“Yes just like that, but move this hand a bit further up” Magnus replied placing his hand on top of the prince’s, sliding it further down the spear to the correct positioning

“Well if I don’t manage to catch a fish, at least I learnt something today,” Alec said with a small laugh.

Today was a big change of pace for Alec and Magnus. After the crowds, noise and dancing of the festival, Magnus thought that taking Alec hunting would be a good balancer. It was only when they got out to Magnus’ usual hunting ground did the prince let him know that he had never hunted before. 

It didn’t come as a big surprise to him. Why would a prince ever have to hunt for his own food? He would have had it served to him on a silver spoon his entire life, but if he wanted to live freely this was a skill he would need to master.

Magnus returned the smile Alec gave him and gestured for him to follow. The pair swam for a little bit before coming to hide behind some rocks where Magnus normally waited.

“Now, the key to hunting fish is not to strike too early. Strike too early and you’ll lose your potential food” Magnus explained, Alec nodded along in acknowledgement. 

“ _But_ , you also don’t want to hesitate either, fish don’t have very long attention spans” 

“So… how do I know when to throw if I don’t want to go too early or too late?” Alec questioned

“Just watch me and then you can have a go” Magnus replied, turning his attention to the school of tuna fish in front of them.

Magnus readied his spear and threw, smiling as it pierced right through a fish and stuck into the ocean floor. 

“See? Not as hard as it looks! Give it a shot” Magnus exclaimed turning back to the prince who was looking slightly intimidated by Magnus’ flawless performance.

“Okay just… just don’t laugh at me” Alec mumbled as he readied his own spear. Magnus could see that Alec’s arms were slightly shaking from nerves.

“Alexander you need to relax, stressing is going to cause you more harm than good” 

The prince paused and looked over to Magnus, a frown settling on his face.  
“Stressing? I’m not stressing what in Poseidon do you mean?” 

“Your arms are shaking like they’re about to fall off, here” Magnus swam forward and gently placed one hand on the bottom of Alec’s bicep and the other on his shoulder.

“Don’t think about it too much, relax and just push. Alright?” Magnus said gently as he adjusted Alec’s arm slightly. Alec was hoping that the sea witch didn’t see the blush that quickly spread across his cheeks and chest as his hands touched him… how was he so soft? 

“Go for it” With his signal, Alec threw his spear. The pointed stick went flying through the air straight towards a fish.

Only for the fish to quickly dart away at the last second, making Alec’s spear stick into the sand.

“Oh” Alec’s voice sounded so small and so heartbroken, like a child who had their favourite toy taken from them.

Magnus needed to fix it, _now_

“Hey it’s fine! I didn’t catch anything for quite some time when I started learning!” Magnus chimed in as he began to swim over to pick up their spears.

When he returned, the sad and defeated look remained on Alec’s face. 

“I really am useless huh? Just a stuck up prince who’s had everything handed to him” Alec sighed as he drifted down to the seafloor, letting his head come to rest on his palm. Magnus also sighed and drifted down next to him, placing the spears onto the floor.

Magnus bumped shoulders with the prince gently “Hey, don’t be so hard on yourself” 

“It’s true though isn’t it? I can’t do anything for myself” Alec continued, his head coming to rest sideways on his tail, facing away from Magnus shamefully.

“Alexander, you may be a prince but from the short time I’ve known you, I can already tell you’re a much better person than those who raised you. Just because you don’t have certain skills doesn’t make you useless as a person, you just have to put in the time and effort to learn those skills” Magnus picked up one of the spears once again and offered to Alec

“And I’m willing to teach you if you’ll let me”

Alec looked between the spear and Magnus a few times before letting out another sigh

“Alright” 

Together, the two practised for hours. Many failed throws were made and Alec almost quit another two times.

Until finally, he hit his mark.

The spear flew through the water fast and quick just as Magnus had instructed him to  
And it landed right in the middle of a giant tuna, pinning it down to the sandy floor.

Alec’s face broke out in a smile as he turned and looked to Magnus.

“I did it! Did you see?!” Alec seemed like a child who had just lost their first tooth, but somehow it was endearing to Magnus.

“I did! Well done Alec you’re-” Magnus cut himself off when he noticed a bit of red coming from Alec’s shoulder “bleeding!”

“Huh?” Alec questioned looking to his shoulder, seeing a medium-sized cut on his skin.

“Oh, I must have cut myself when I threw the spear,” Alec said sheepishly making Magnus smirk and let out a small laugh.

“Come here,” Magnus said, placing his hands on Alec’s shoulder as he let gentle healing magic wash over the injury. The skin knitted itself back together and any sign of the injury disappeared, leaving Alec’s skin clear once more.

“That’s um, that’s pretty impressive” Alec muttered gesturing to Magnus’ magic making the sea witch chuckle.

“Thank you darling” He replied as he continued to work.

“I thought you were good at potions and stuff like that?” Alec questioned as he ran his hand over his shoulder, his skin was just as smooth as it felt before he got the cut.

“My expertise is potions and spells, but I know a little about healing magic. Mostly minor cuts and bruises, it’d be a different story if you got a spear through the chest or something, then we might have a problem” 

“I’ll keep that in mind, now I wanna see what I caught!” Alec exclaimed swimming off to collect his hunted tuna, leaving an amused Magnus in his wake.

“Royalty” He sighed with a fond smile before quickly swimming after Alec

**Notes for the Chapter:**

> It's been a while huh?
> 
> Follow my tumblr!
> 
> http://gummi-stories.tumblr.com/


	4. Chapter 4

**Summary for the Chapter:**

> History class is now in session

Large books landed heavily in front of Alec, shocking him out of his daydream

“It’s history lesson time Alexander,” Magnus said as he drifted down next to Alec, picking up one of the books and placing it in the prince’s lap. 

Alec frowned and placed a hand on the old and worn book, shooting Magnus a look of confusion

“How is this supposed to convince me of anything? I have to do plenty of study at home” 

Magnus didn’t respond as he opened the book on Alec’s lap, pointing to the first sentence on the page. From the colouring of the page and the font alone, Alec could tell these were probably very ancient books.

“I guarantee that you’ve never been told the entire truth, humour me” Magnus urged which made Alec sigh

“I’m not going to like what I find in these… am I?” Alec questioned 

Magnus’ first instinct was to reassure Alec, tell him that it’d all be fine and that this was just for a bit of history from his side of life, the downworlder’s side. But the words died on his tongue, not wanting to lie to Alec

The history of his people was full of blood, war, agony and torture. The rule of the Lightwoods was ruthless from the beginning, Magnus had lost many friends to the royals. 

From Magnus’ lack of response, Alec had his answer. Steeling himself, Alec began to read, delving into the past he had never had access to 

“WHY?!” Magnus jumped as Alec all but shouted as he jumped up from his seat, tossing the book he had been reading for two and a half hours carelessly to the side. The prince swam across the room, hands tangled in his hair and clearly distressed based on the harsh angered breaths escaping him

Retrieving the book and gently placing it back on the table, Magnus slowly approached the prince, making sure to give him a bit of space as he was clearly upset.

“How… I don’t understand. They were innocent people, families, children… just slaughtered. All because of ‘unpure blood’?” Alec’s voice was low and unsure, the young prince was clearly struggling to process what was in the book.

Magnus sighed before placing a gentle hand on Alec’s shoulder, feeling the tense muscles under his hand. 

“I know it’s a lot Alexander and I’m sure it doesn’t make much sense, but I thought you deserved the truth. I apologise if I pushed you too far” Magnus said softly, slightly fearful that he really had pushed the prince past his limit.

Suddenly, much to Magnus’ surprise, Alec spun around and wrapped his arms around the sea witch, his embrace tight and desperate.

“I’m so sorry Magnus”

Magnus couldn’t move from shock. Here he was, with one of the Lightwood children in his home.

_and he was apologizing to him_

Never in all his days did Magnus believe he would hear those words from a Lightwood.

Slowly, Magnus moved to return the embrace feeling Alec shaking under his arms, distraught from his newfound knowledge.

“It’s alright Alexander” The sea witch hushed the prince, at this moment Magnus was hit with the fact that Alec was just a young man. A lost, confused and distressed child. In his short twenty-one years of life, Alec had barely learnt anything about his kingdom and the bloody ruins it was built on, having so much taught to him at once was no doubt taking its toll on him.

“Would you like something to drink? Maybe we could sit down and talk about it?” Magnus suggested pulling back, his heart aching slightly seeing Alec’s eyes were red from crying.

Alec sniffled and nodded, his hazel eyes meeting Magnus’

“I’d like that” 

Magnus gave Alec a comforting smile and placed a hand on the other’s cheek, his touch lingering a bit too long, but Alec didn’t seem to be complaining with the sad smile he returned.

Magnus pulled his hand away when he realized what he was doing and coughed, turning to swim towards his kitchen area.

“I can make something strong if you like or if you’d prefer I could always” Magnus’ voice faded as he swam further into the cave, leaving Alec alone in his living area.

The prince’s mind was still reeling from what he had read, he knew that his ancestors had been bad but he had never expected their history to be something like _that_

If he was to marry Lydia and become the next king of Alicante, he wouldn’t have much power to make any changes to the kingdom. His parents would still do most of the ruling with him being the “puppet of power”, alongside the council of bigots, Alec liked to call them.

The old grumpy bastards hated anything different, anything not like them, anything _unpure_

It was one of the many reasons Alec wanted Magnus to altar his mind, make it easier for him to be able to fall into his new role as king.

Fleeing wasn’t an option, he had no way of escaping for good

He also had nothing to escape for… right?

Alec felt his heart skip a beat when his mind returned to Magnus, it had been doing that a lot in the past 24 hours.

Shaking off the ridiculous feeling, Alec sighed and sat back down waiting for Magnus’ return.

They still had plenty of history to get through

**Notes for the Chapter:**

> yes hello I'm still here, just been lurkin

**Author's Note:**

> I hope you enjoyed!
> 
> I hope this goes the way I intend it to go! :D
> 
> If you liked please chuck me a kudos and a comment, I love to read them <3


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